Your Transmitter Diagram (mxmit) is unsuitable for UHF due to poor stability in that design, the data-rate will be very slow (eg 300 baud), with a very short range (only a few metres), and create large amounts of inter-modulation product that will almost certainly be well out-of-band (it will NEVER pass any form of approval), however the general frequency will be determined by the formula...

f=1/(2 x pi x (rt (L1 x (C2 + C3))))

where

f = frequency in Hertz
pi = 3.141592
rt = square root of 2
L1 is the value of L1 from your circuit in Henries
C2 + C3 is the combined value of C2 + C3 from your circuit in Farads

You will have to do two calculations... one with C3 at minimum value, and another with C3 at maximum value, and that will determine your tuning range.